I've got 10 users (win xp + office so outlook 2003 not connected to internet just a small lan using a w2k3 server with pop service) and I want to use something for sharing contact, calendar ... using outlook 2003 but without an Exchange server.

Not being an Exchange user myself, I can't tell you anything about any of these products, or recommend any particular one for your situation. If one of them works for you, do please let us know here on the forum._________________Take back the PC! http://www.goodbyemicrosoft.net

It´s now 2014 and there is a kick-ass alternative! Open source and native drop-in! www.zentyal.org

Enjoy!

I'm glad someone brought up Zentyal. I'm evaluating it at home for my personal email and have many things to say, good and bad.

For a while, it didn't have a replacement for ActiveSync (required for native compatibility with Outlook) but that has been remedied in version 5.1. It doesn't do auto-discovery, but it's enough that you can set up your phone to pull email without complex configuration or opening IMAP and SMTP ports (that way be fiery dragons without a firewall).

It's not only a drop-in replacement for Exchange, it's also a drop-in replacement for Active Directory. In fact, it was developed as a drop-in replacement for Microsoft Small Business Server after it was discontinued, likely in an effort to push people onto cloud services. The only thing it doesn't supply is a drop-in replacement for SharePoint, but there are some open-source alternatives available for that.

It's by no means perfect - some of the interfaces provided by Zentyal leave much to be desired. There are limitations yet to be resolved - for instance, you can't currently share mailboxes without a whole lot of fiddling. You can't set up multiple email addresses, and you can't change email addresses without deleting and recreating accounts. Joining an existing Windows domain appears to have problems - I'm trying to do this now in a test environment with Server 2016 Essentials (albeit at 2008R2 domain and forest functional level) and Zentyal 5.1, and it's not even joining, let alone taking on its domain roles.

It's certainly worth considering, but do your testing first to make sure it will work in your environment before committing.